chore: SHA-pin all GitHub Actions across workflows

Mutable action references (@v4, @V3, …) are the same failure mode that
took out tj-actions/changed-files (23k+ repos compromised in Q1 2026)
and trivy-action. An attacker who compromises an action's maintainer
account can silently re-point a tag at a malicious SHA, and every
workflow that references that tag pulls the new code on the next run.

Pinning each action by full commit SHA — with the human-readable tag
preserved as a trailing comment — closes that vector. Dependabot's
github-actions ecosystem (enabled in the companion commit) proposes
SHA bumps with the new tag annotated in the PR body, so updates remain
reviewable.

All four workflows pinned; SHAs resolved against current refs as of
this commit, no behavioral change intended.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: cailmdaley

.github/workflows/cd.yml

@@ -13,10 +13,10 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@ee0669bd1cc54295c223e0bb666b733df41de1c5 # v2.7.0
 
       - name: Set up conda
-        uses: conda-incubator/setup-miniconda@v2
+        uses: conda-incubator/setup-miniconda@9f54435e0e72c53962ee863144e47a4b094bfd35 # v2.3.0
         with:
           auto-update-conda: true
           python-version: 3.9
@@ -38,7 +38,7 @@ jobs:
           sphinx-build -E docs/source docs/_build
 
       - name: Deploy API documentation
-        uses: peaceiris/actions-gh-pages@v3.5.9
+        uses: peaceiris/actions-gh-pages@cf301857435c1f95963b21d58f452a7617770d60 # v3.5.9
         with:
           github_token: ${{ secrets.GITHUB_TOKEN }}
           publish_dir: docs/_build

.github/workflows/ci-release.yml

@@ -19,7 +19,7 @@ jobs:
         python-version: [3.11]
 
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5 # v4.3.1
 
       - name: Install Linux dependencies
         if: runner.os == 'Linux'
@@ -35,7 +35,7 @@ jobs:
           brew reinstall gcc
 
       - name: Set up conda
-        uses: conda-incubator/setup-miniconda@v3
+        uses: conda-incubator/setup-miniconda@fc2d68f6413eb2d87b895e92f8584b5b94a10167 # v3.3.0
         with:
           auto-update-conda: true
           python-version: ${{ matrix.python-version }}

.github/workflows/deploy-image.yml

@@ -11,39 +11,39 @@ jobs:
       packages: write
     steps:
       - name: Checkout repository
-        uses: actions/checkout@v4
+        uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5 # v4.3.1
 
       - name: Log in to the Container registry
-        uses: docker/login-action@v3
+        uses: docker/login-action@c94ce9fb468520275223c153574b00df6fe4bcc9 # v3.7.0
         with:
           registry: ${{ env.REGISTRY }}
           username: ${{ github.actor }}
           password: ${{ secrets.GITHUB_TOKEN }}
 
       - name: Set up Docker Buildx
-        uses: docker/setup-buildx-action@v3
+        uses: docker/setup-buildx-action@8d2750c68a42422c14e847fe6c8ac0403b4cbd6f # v3.12.0
         with:
           driver-opts: network=host
 
       # Two parallel tag sets. `dev` is the default (no suffix, e.g. `:latest`,
       # `:develop`); `runtime` carries a `-runtime` suffix.
       - name: Tags — dev (default)
         id: meta-dev
-        uses: docker/metadata-action@v5
+        uses: docker/metadata-action@c299e40c65443455700f0fdfc63efafe5b349051 # v5.10.0
         with:
           images: ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}
 
       - name: Tags — runtime
         id: meta-runtime
-        uses: docker/metadata-action@v5
+        uses: docker/metadata-action@c299e40c65443455700f0fdfc63efafe5b349051 # v5.10.0
         with:
           images: ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}
           flavor: |
             suffix=-runtime,onlatest=true
 
       # Build runtime first (smaller, used to smoke-test pipeline binaries)
       - name: Build runtime (load)
-        uses: docker/build-push-action@v6
+        uses: docker/build-push-action@10e90e3645eae34f1e60eeb005ba3a3d33f178e8 # v6.19.2
         with:
           context: .
           target: runtime
@@ -70,7 +70,7 @@ jobs:
 
       # Build dev (reuses cached `base` layer)
       - name: Build dev (load)
-        uses: docker/build-push-action@v6
+        uses: docker/build-push-action@10e90e3645eae34f1e60eeb005ba3a3d33f178e8 # v6.19.2
         with:
           context: .
           target: dev
@@ -90,7 +90,7 @@ jobs:
 
       # Push both targets
       - name: Push runtime
-        uses: docker/build-push-action@v6
+        uses: docker/build-push-action@10e90e3645eae34f1e60eeb005ba3a3d33f178e8 # v6.19.2
         with:
           context: .
           target: runtime
@@ -100,7 +100,7 @@ jobs:
           cache-from: type=gha
 
       - name: Push dev
-        uses: docker/build-push-action@v6
+        uses: docker/build-push-action@10e90e3645eae34f1e60eeb005ba3a3d33f178e8 # v6.19.2
         with:
           context: .
           target: dev

.github/workflows/doc-tests.yml

@@ -8,10 +8,10 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@ee0669bd1cc54295c223e0bb666b733df41de1c5 # v2.7.0
 
       - name: Set up conda
-        uses: conda-incubator/setup-miniconda@v2
+        uses: conda-incubator/setup-miniconda@9f54435e0e72c53962ee863144e47a4b094bfd35 # v2.3.0
         with:
           auto-update-conda: true
           python-version: 3.8
@@ -33,7 +33,7 @@ jobs:
           sphinx-build -E docs/source docs/_build
 
       - name: Archive API build
-        uses: actions/upload-artifact@v2
+        uses: actions/upload-artifact@82c141cc518b40d92cc801eee768e7aafc9c2fa2 # v2.3.1
         with:
           name: api-docs
           retention-days: 14